Akashi-san
> > > > + > > > > +* FWU metadata 1 > > > > +* U-Boot 1 > > > > +* OP-TEE 1 > > > > +* FWU metadata 2 > > > > +* OP-TEE 2 > > > > +* U-Boot 2 > > > > +* ESP > > > > +* rootfs > > > > + > > > > +When generating the partitions, a few aspects need to be taken care > > > > +of. Each GPT partition entry in the GPT header has two GUIDs:: > > > > + > > > > +* PartitionTypeGUID > > > > +* UniquePartitionGUID > > > > + > > > > +The PartitionTypeGUID value should correspond to the > > > > +``image_type_uuid`` field of the FWU metadata. This field is used to > > > > +identify a given type of updatable firmware image, e.g. U-Boot, > > > > +OP-TEE, FIP etc. This GUID should also be used for specifying the > > > > +`--guid` parameter when generating the capsule. > > > > + > > > > +The UniquePartitionGUID value should correspond to the ``image_uuid`` > > > > +field in the FWU metadata. This GUID is used to identify images of a > > > > +given image type in different banks. > > > > > > Well, what is not clear to me here is: > > > - who is responsible to set up FWU metadata and when > > > > Initially, when the board is being provisioned, the metadata is > > supposed to be installed on two separate partitions. This is described > > under "Setting up the device for GPT partitioned storage". > > > > > - how FWU metadata is related to fw_images and update_info > > > which are used in normal case, which is mentioned in > > > develop/uefi/uefi.rst > > > > The entire update process is the same as the UEFI capsule update. This > > is being highlighted in the first paragraph under "Performing the > > Update". > > I think of developers. > > For instance, as I mentioned above, image_type_uuid/image_index in FWU > metadata > must match with the ones in fw_images. > And how about update_info, especially dfu_string? This field won't be used > in A/B update IIUC. > There are a couple of points that developers should be aware. > That is why I suggested the whole explanation is in one place. > > > I have also added a paragraph under "Performing the update" > > which specifies how the image index value used with the FWU feature > > enabled is different from the normal capsule update. > > > > > > > > I know the whole text here is dedicated to A/B update, but I think > > > it would also be helpful to have a single document which covers both cases > > > for developers to understand how differently FWU is configured for those > > > cases. > > > > I would think that it would be more clear to have a separate document > > for the FWU updates. In any case, the fwu_updates.rst is under the > > same directory as the uefi.rst which explains the normal capsule > > update functionality. There would also be addition of the section for > > the FWU updates on platforms using MTD based devices. So I think it > > would be better to keep the documents separate. Even if we move the > > content in fwu_updates.rst under uefi.rst, the actual update process > > would still be explained by the section under > > 'uefi_capsule_update_ref'. Do you see difficulty in understanding the > > FWU update feature being kept in a separate file? > > Yes. > > I don't care whether the text is contained in a physically-single document, > but do expect that the normal case and A/B update are described (in different > sections) under the logically-same chapter for better understanding of > differences. That would make the document quite big though wouldn't it? Wouldn't it be a bit more readable to add a link in the capsule update documentation pointing to the FWU functionality? IOW add a paragraph in capsule updates describing the basics and then have a link the the existing FWU documentation. Regards /Ilias > -Takahiro Akashi > > > > -sughosh > > > > > > > > -Takahiro Akashi > > > > > > > + > > > > +Similarly, the FWU specification defines the GUID value to be used > > > > +for the metadata partitions. This would be the PartitionTypeGUID for > > > > +the metadata partitions. > > > > + > > > > +When generating the metadata, the ``image_type_uuid`` and the > > > > +``image_uuid`` values should match the *PartitionTypeGUID* and the > > > > +*UniquePartitionGUID* values respectively. > > > > + > > > > +Performing the Update > > > > +--------------------- > > > > + > > > > +Once the storage media has been partitioned and populated with the > > > > +metadata partitions, the UEFI capsule-on-disk update functionality can > > > > +be used for performing the update. Refer to the section > > > > +:ref:`uefi_capsule_update_ref` for details on how the update can be > > > > +invoked. > > > > + > > > > +On a successful update, the FWU metadata gets updated to reflect the > > > > +bank from which the platform would be booting on subsequent boot. > > > > + > > > > +Based on the value of bit15 of the Flags member of the capsule header, > > > > +the updated images would either be accepted by the U-Boot's UEFI > > > > +implementation, or by the Operating System. If the Operating System is > > > > +accepting the firmware images, it does so by generating an empty > > > > +*accept* capsule. The Operating System can also reject the updated > > > > +firmware by generating a *revert* capsule. The empty capsule can be > > > > +applied by using the exact same procedure used for performing the > > > > +capsule-on-disk update. > > > > + > > > > +The task of accepting the different firmware images, post an update > > > > +may be done by multiple, separate components in the Operating > > > > +System. To help identify the firmware image that is being accepted, > > > > +the accept capsule passes the image GUID of the firmware image being > > > > +accepted. The relevant code in U-Boot then sets the Accept bit of the > > > > +corresponding firmware image for which the accept capsule was > > > > +found. Only when all the firmware components in a bank have been > > > > +accepted does the platform transition from trial state to regular > > > > +state. > > > > + > > > > +The revert capsule on the other hand does not pass any image GUID, > > > > +since reverting any image of the bank has the same result of the > > > > +platform booting from the other bank on subsequent boot. > > > > + > > > > +Generating an empty capsule > > > > +--------------------------- > > > > + > > > > +The empty capsule can be generated using the mkeficapsule utility. To > > > > +build the tool, enable:: > > > > + > > > > + CONFIG_TOOLS_MKEFICAPSULE=y > > > > + > > > > +Run the following commands to generate the accept/revert capsules:: > > > > + > > > > +.. code-block:: bash > > > > + > > > > + $ ./tools/mkeficapsule \ > > > > + [--fw-accept --guid <image guid>] | \ > > > > + [--fw-revert] \ > > > > + <capsule_file_name> > > > > + > > > > +Some examples of using the mkeficapsule tool for generation of the > > > > +empty capsule would be:: > > > > + > > > > +.. code-block:: bash > > > > + > > > > + $ ./tools/mkeficapsule --fw-accept --guid <image guid> \ > > > > + <accept_capsule_name> > > > > + $ ./tools/mkeficapsule --fw-revert <revert_capsule_name> > > > > + > > > > +Links > > > > +----- > > > > + > > > > +* [1] https://developer.arm.com/documentation/den0118/a/ - FWU > > > > Specification > > > > +* [2] > > > > https://git.codelinaro.org/linaro/dependable-boot/mbfw/uploads/6f7ddfe3be24e18d4319e108a758d02e/mbfw.pdf > > > > - Dependable Boot Specification > > > > diff --git a/doc/develop/uefi/index.rst b/doc/develop/uefi/index.rst > > > > index 7e65dbc5d5..e26b1fbe05 100644 > > > > --- a/doc/develop/uefi/index.rst > > > > +++ b/doc/develop/uefi/index.rst > > > > @@ -13,3 +13,4 @@ can be run an UEFI payload. > > > > uefi.rst > > > > u-boot_on_efi.rst > > > > iscsi.rst > > > > + fwu_updates.rst > > > > diff --git a/doc/develop/uefi/uefi.rst b/doc/develop/uefi/uefi.rst > > > > index 941e427093..b5c83db65a 100644 > > > > --- a/doc/develop/uefi/uefi.rst > > > > +++ b/doc/develop/uefi/uefi.rst > > > > @@ -277,6 +277,8 @@ Enable ``CONFIG_OPTEE``, ``CONFIG_CMD_OPTEE_RPMB`` > > > > and ``CONFIG_EFI_MM_COMM_TEE` > > > > > > > > [1] https://optee.readthedocs.io/en/latest/building/efi_vars/stmm.html > > > > > > > > +.. _uefi_capsule_update_ref: > > > > + > > > > Enabling UEFI Capsule Update feature > > > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > > > > > @@ -377,6 +379,14 @@ following command:: > > > > > > > > dfu list > > > > > > > > +When the FWU Multi Bank Update feature is enabled on the platform, the > > > > +image index is used only to identify the image index with the image > > > > +GUID. The image index would not correspond to the dfu alt number. This > > > > +is because the FWU feature supports multiple partitions(banks) of > > > > +updatable images, and the actual dfu alt number to which the image is > > > > +to be written to is determined at runtime, based on the value of the > > > > +update bank to which the image is to be written. > > > > + > > > > When using the FMP for FIT images, the image index value needs to be > > > > set to 1. > > > > > > > > -- > > > > 2.34.1 > > > >
